A mountain biker coasts on Marin County open space, where rangers are trying to cut friction between cyclists and other park users.

A mountain biker coasts on Marin County open space, where rangers are trying to cut friction between cyclists and other park users.

Photo: Michael Macor, The Chronicle

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Maureen Pardi (front) bikes in Marin on April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 mph speed limit for mountain bikers on Marin County open space land. less

Maureen Pardi (front) bikes in Marin on April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 mph speed limit for mountain bikers on ... more

Photo: Susana Bates, Special To The Chronicle

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Herman Ng gets his tire fixed by John Marlowe at Mt. Tam Bikes in Mill Valley on April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 mph speed limit for mountain bikers on Marin County open space land. less

Herman Ng gets his tire fixed by John Marlowe at Mt. Tam Bikes in Mill Valley on April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 ... more

George Travin and Matt Weeder speak to the Chronicle at Mt. Tam Bikes in Mill Valley on Friday, April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 mph speed limit for mountain bikers on Marin County open space land. less

George Travin and Matt Weeder speak to the Chronicle at Mt. Tam Bikes in Mill Valley on Friday, April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to ... more

A mountain biker is seen in Marin on April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 mph speed limit for mountain bikers on Marin County open space land. less

A mountain biker is seen in Marin on April 1, 2016. Marin County park rangers are starting a new program to use radar guns to monitor, and later to enforce, the 15 mph speed limit for mountain bikers on Marin ... more

Photo: Susana Bates, Special To The Chronicle

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Mountain bikers beware: Marin rangers to use radar guns

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The long arm of the law is going to be holding a radar gun on the majestic mountain bike trails of Marin County, and the other hand is probably going to be holding a book full of citations.

Beginning this month, park rangers will be staking out open space areas where mountain bikers, hikers, dog walkers and horseback riders have been known to speak words to one another that are less than bucolic. Bikers speeding along the dirt paths where modern mountain biking was born will be eligible for tickets as part of a campaign to reduce friction between trail users.

The county parks department said this week that it will assign its two sheriff’s deputies to occasional bike speed stakeouts, using two recently acquired radar guns. Exactly where the deputies will be assigned is top secret — it could be at any of the agency’s 34 open space areas, encompassing 16,000 acres.

“But the ridgetops above Mill Valley, Fairfax and San Rafael would be likely places,” said Max Korten, assistant director of Marin County Parks.

Fiedler admitted that he was probably going closer to 30 mph when he lost control and crashed his mountain bike Friday on Old Railroad Grade north of Mill Valley. His arms, hands and knees were bloody, but he smiled and said he was OK. Fiedler said he tries his best to share the trail, even when the trail has other ideas about how to treat him in return.

“I’m always polite and say, ‘Howdy,’” he said. “But I also like the excitement of going fast. To keep it at 15 mph when you’re coming down from the top, you’re going to be squeezing your brakes the whole time. What fun is that?”

Rogue 1 percent

Maureen Pardi, who was taking her first mountain bike ride with her husband, Marco, said she was OK with the radar guns and the speed limit.

“But maybe I’d feel different if I was more experienced,” she said.

Marco Pardi said a speed limit is a good idea, too. Even with no speedometer on his bike, he said, he knows what 15 mph feels like. Taking his first bike ride with his wife, he said, was challenge enough.

“It’s really all about being in control,” he said. “Ninety-nine percent of the bikers are courteous and respectful, but there’s always some who aren’t.”

Korten said the parks department’s idea is to “assist and educate folks about speeding” and that nothing has worked better, educationwise, than the 64 citations and warnings issued by radar-toting sheriff’s deputies over the past year on the popular Mill Valley-Sausalito trail that passes through wetlands and alongside a soccer field.

The enforcement campaign on that trail worked so well, Korten said, that park directors decided to try it throughout the county.

“We noted a decrease in speed,” Korten said. “The number of problems went down.”

Trying it out

The open space campaign will begin with several weeks of radar speed checks that could lead, within weeks, to warnings and citations.

In the East Bay, rangers also patrol popular off-road bike trails to monitor conduct and keep the peace, said East Bay Regional Parks spokeswoman Carolyn Jones. Its rangers use a light-based speed gun, similar to radar, said Sgt. David Greaney of the park police.

Heavily used paved trails, such as the Iron Horse and George Miller trails, are frequently patrolled. In the past year, park police issued about two dozen citations and warnings.

By law, a moving violation received by a bicyclist is similar to one received by an automobile driver and counts against his or her driving record. Fines vary but typically cost several hundred dollars, and citations can also increase the cost of vehicle insurance.

At the Camino Alto open space between Mill Valley and Larkspur, dog walker Beth Greer was walking her poodle, Jake. Speedy mountain bikes, she said, are a dog walker’s nightmare.

“Oh, my God, they come whizzing up, out of nowhere, and they yell at you to move over,” she said. “It’s scary.”

Amy Quaranta said she and her Labrador retriever, Arlo, have had “plenty of close calls, but we’ve never been hit.”

She said rangers ticket dog walkers all the time for not picking up poop, so rangers ticketing other trail users would not be amiss.

Where it all began

The modern sport of mountain biking was born in 1977, when Mill Valley’s own Joe Breeze crafted the first lightweight, high-end bike and began riding it on Mount Tam. Previously, off-road bikers rode heavy clunkers and modified kiddie bikes.

Times have changed. At the Tam Bikes store in Mill Valley, a top-of-the-line S-Works Epic mountain bike with electronic shifting sells for $11,500.

For aficionados, 15 mph on a such a fine bike “feels like crawling,” said mechanic Matt Weeder. “People come from all over the world to ride mountain bikes on Mount Tam. We don’t want to discourage people from doing that, do we?”

Herman Ng, who had dropped by the store to have a tire fixed, said he rings his bell and calls out to hikers. That’s the solution, he said — not speed traps that will take the fun out of the sport.

“Fifteen miles an hour is a drag,” he said. “I believe in sharing the trail. But these bikes are meant to go a lot faster than that.”

Bikers say they can be just as scared of dogs and horses as hikers, dog walkers and horseback riders can be of a fast-moving biker.

“It’s true, bikes can freak people out when they fly around a corner and come up on somebody,” Weeder said. “But a dog that’s not on a leash can freak out someone on a bike. Everybody just needs to be a little more considerate of everyone else.”